Thin, planar, and relatively large area light sources are needed in many applications. Back lights must often be provided for LCD's to make them readable in all environments. As is known, LCD's require a minimum amount of light in order to be read. For some environments, relatively bright lights are required to permit the reading of LCD displays.
One of the problems associated with providing light for LCD's is that the lights should take up as small an area as possible. Thus, thin back lights are desired to preserve as much as possible the LCD's traditional strengths of thin profile, low cost, and versatility of use, while permitting readability of the LCD's at all times. Lamps for use in the avionic environment, such as airplane cockpits, are preferably lightweight and thin, but must put out a high intensity of light in order to be useful for reading an LCD.
In the past, planar fluorescent lamps have not had sufficient light output to be useful in airplane cockpits, or for backlights for single or double-sided signage, with the ability to tile into large areas. For example, prior art commercial tubes, such as those 4 feet or 8 feet long, generally output 2,500 foot-lamberts when new. Unfortunately, such light sources are tubes and are not flat, planar fluorescent lamps. Unfortunately, flat fluorescent lamps generally have not been able to achieve the light output which is achievable by tubes. It is, therefore, desirable to provide a flat fluorescent lamp having a high light output and uniform brightness.